Conventionally, a window system is known which enables an arrangement of a plurality of windows as display areas on a screen and displays a screen for each window. This window system allows the user to watch a plurality of contents simultaneously by arranging a plurality of windows on the screen.
When display positions of a plurality of windows overlap due to a user's window operation, only one of contents of windows is displayed in this overlapping range. Which window to display is determined based on the display priority of each window. The window having the highest priority is an active window. Further, the priority of each window changes according to the user's window operation. When a plurality of windows overlap, windows other than the window displayed in the overlapping range are completely hidden by other windows and are not displayed on the screen, or are partially hidden. In this case, a user's interest is mainly directed toward windows which are not hidden by the other windows, beginning with the active widow. Hence, even though content of the window is displayed in a range (hereinafter, referred to as “visible area”) which is not hidden in a window which is partially hidden (which becomes partially invisible), the user's interest is not much directed toward content of this visible area. That is, there are cases where the visible area of the window which is partially hidden is an area which is meaningless for the user.
Patent Document 1 discloses a technique of changing a display size and display position of each window as a technique related to overlapping of windows. More specifically, when the user selects a plurality of objects displayed on the screen, a browsing device according to this technique initially arranges a window which displays content, in respective display positions of the selected objects. Then, in a range where the degree of overlapping of windows enables contents to be simultaneously browsed, the browsing device enlarges the display size of each window, and changes the display position of each window.